How to Avoid Common Pool Maintenance Mistakes

Whether you’re a new pool owner or have owned one for years, proper pool maintenance ensures your inground pool remains a sparkling oasis, extends its lifespan, and minimizes costly repairs. If you’re a fiberglass pool owner, you probably have heard that fiberglass pools are the lower maintenance option among pool types. However, lower maintenance does not mean no maintenance. The following tips can help you avoid the common mistakes people make when caring for their inground pool.

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Tip 1: Balance your Water with Fiberglass In Mind

Failing to monitor water chemistry regularly is one of the most common—and most costly—mistakes pool owners make. The water may look crystal clear, but that doesn’t mean it’s maintained properly. Poor water chemistry and balance can silently cause scaling, chalking, and permanent damage to your fiberglass pool’s surface.

With fiberglass, focus on the chemistry that matters most:

  • Maintain pH between 7.2–7.4

  • Keep calcium hardness below 120 ppm (If above 120 ppm, must use a chelating stain/metal and scale control product.)

  • Chlorine should stay between 1–3 ppm

  • Use a stain and scale control product consistently

Rather than relying solely on LSI, which was developed with concrete pools in mind, fiberglass pool care is about tight control of a few core values. By carefully managing calcium levels and avoiding high pH —especially in salt pools—you’ll help preserve the beauty of your gelcoat finish for the long term.

Use a high-quality test kit for the best results, or have your water tested professionally. Just be sure to bring water samples in promptly—heat or delay (sitting in a car all day) can alter results.

For the most information on recommendations, refer to our Fiberglass Pool Care Guide and Owner’s Manual, where we outline specific ranges and which chemicals to avoid.

Tip 2: Backwash Regularly

Many pool owners start the season off by backwashing their filters once per week. As the season progresses, they often aren’t as dedicated to it. Your filter plays an essential role in the continued enjoyment of your pool, and proper backwashing can reduce your pool maintenance costs in the long run. Some reasons you should backwash regularly include the following.

  • Efficiency: A clean filter is more effective at trapping debris. A clogged filter can’t perform efficiently, putting more strain on your pool pump and reducing its lifespan.
  • Water Quality: Regular backwashing helps maintain clear and sanitary pool water. A dirty filter can harbor bacteria and allow more contaminants to circulate into the pool.
  • Prevent Damage: Over time, excessive pressure from a dirty filter can cause damage to the pool’s filtration system. Regular backwashing helps prevent such issues.

A clean, efficient filter system improves overall water quality—and helps keep your pool water looking and feeling great.

Tip 3: Keep Up Your Water Level 

Maintaining the water level at the midpoint of the skimmer opening allows your pool’s systems to operate correctly. The skimmer is designed to pull debris from the pool’s surface before it sinks to the bottom of the pool, becoming harder to remove. If the water level is too high, the skimmer door may not work correctly, reducing its efficiency at collecting surface debris. If the water is too low, the skimmer may suck in air, which can lead to airlocks or damage the pool pump by causing it to run dry.

The proper water level also provides balanced circulation. The pool pump must pull water through the skimmer for filtration and chemical treatment. Maintaining the correct level helps ensure that the water circulates properly, distributes chemicals evenly, and keeps the temperature consistent throughout.

In fiberglass pools, maintaining proper water level is also critical to prevent structural stress. Extremely low water levels can lead to wall bulging, or even floating due to groundwater pressure, which is why most manufacture’s warranty is voided when the water level is dropped below the skimmer.

Protect your pool’s structure by checking and maintaining your water level consistently.

Tip 4: Be Selective About What You Use

Not all chemicals and tools are safe for fiberglass pools. Using the wrong products can lead to staining, discoloration, and surface damage.

Good Chemicals for Fiberglass Pools

  1. pH Balancers: Keeping the pH level between 7.2 and 7.4 is crucial. To maintain this balance, use pH increasers (soda ash) or decreasers (muriatic acid or sodium bisulfate) are acceptable.
  2. Alkalinity Increasers: Baking soda (sodium bicarbonate) is commonly used to maintain total alkalinity, which should be kept between 80 and 120 ppm (parts per million) to stabilize pH levels.
  3. Non-Copper Algaecides: Avoid algaecides that contain copper, as they can stain the fiberglass. Look for polyquat algaecides, which are safe for fiberglass.
  4. Most Chlorine Types: Keep total chlorine at 1 to 3 ppm. When your water is balanced to LSI, you will need less chlorine. High chlorine levels can damage the gelcoat finish over time.

Harmful Chemicals for Fiberglass Pools

  1. Completely avoid Calcium Hypochlorite (A Form of Chlorine That Contains Calcium) and Calcium Increasers and other products that contain Calcium.
  2. Avoid “shocking” the pool with high doses of chlorine, especially if not diluted properly, as it can lead to discoloration and damage to the fiberglass surface.
  3. Copper-based algaecides can stain fiberglass surfaces, leading to blue-green stains that are difficult to remove.

Good Tools for Fiberglass Pools

  1. Soft-Bristle Brushes: Use soft nylon brushes to clean the pool’s sides and bottom. Fiberglass surfaces are relatively delicate, and using soft brushes will prevent scratches.
  2. Manual or Automatic Cleaners: Ensure that any automatic pool cleaner is suitable for fiberglass pools, typically those that do not require connection to the pool’s filtration system and operate gently.

Tools to Avoid in Fiberglass Pools

  1. Never use wire brushes or abrasive tools, as they can scratch and damage the gelcoat finish.
  2. Some heavy-duty vacuums designed for concrete pools can be too abrasive for fiberglass surfaces.
  3. When maintaining a fiberglass pool, following the manufacturer’s specific recommendations for chemicals and cleaning tools is crucial.

Final Thoughts

Keep a regular pool maintenance schedule. As with many things in life, consistency is vital. Developing a regular, thorough, and routine maintenance schedule helps keep your pool in tip-top shape. Above all, the most significant maintenance mistake is not doing maintenance.